Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.
Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, P.R. China.
Angew Chem Int Ed Engl. 2017 Jan 19;56(4):997-1001. doi: 10.1002/anie.201609230. Epub 2016 Dec 15.
We show graphene oxide (GO) greatly suppresses the growth and recrystallization of ice crystals, and ice crystals display a hexagonal shape in the GO dispersion. Preferred adsorption of GO on the ice crystal surface in liquid water leads to curved ice crystal surface. Therefore, the growth of ice crystal is suppressed owing to the Gibbs-Thompson effect, that is, the curved surface lowers the freezing temperature. Molecular dynamics simulation analysis reveals that oxidized groups on the basal plane of GO form more hydrogen bonds with ice in comparison with liquid water because of the honeycomb hexagonal scaffold of graphene, giving a molecular-level mechanism for controlling ice formation. Application of GO for cryopreservation shows that addition of only 0.01 wt % of GO to a culture medium greatly increases the motility (from 24.3 % to 71.3 %) of horse sperms. This work reports the control of growth of ice with GO, and opens a new avenue for the application of 2D materials.
我们表明氧化石墨烯（GO）能显著抑制冰晶的生长和再结晶，并且在 GO 分散体中冰晶呈现出六边形形状。在液态水中，GO 优先吸附在冰晶表面，导致冰晶表面弯曲。因此，由于吉布斯-汤普森效应，即弯曲表面降低了凝固温度，冰晶的生长受到抑制。分子动力学模拟分析表明，与液态水相比，GO 基面上的氧化基团由于石墨烯的蜂窝状六边形支架与冰形成更多的氢键，从而为控制冰形成提供了分子水平的机制。GO 在冷冻保存中的应用表明，仅向培养基中添加 0.01wt%的 GO 就能极大地提高马精子的活力（从 24.3%提高到 71.3%）。这项工作报道了利用 GO 控制冰的生长，并为二维材料的应用开辟了新途径。
